1. Field of the Invention
The present invention relates to an apparatus for calculating the intensity of an electromagnetic field. The calculation apparatus according to the present invention can easily calculate the intensity of electromagnetic fields radiated from an electronic circuit device at high speed and with high precision.
2. Description of the Related Art
In a design process of an electronic circuit device including printed-circuit boards and housing, it is very important to calculate the intensity of the electromagnetic fields radiated therefrom.
In general, if the current flowing through each part of an electronic circuit device having an optional shape (structure) can be known, it is easy to calculate the intensity of the electromagnetic fields radiated therefrom by using known theory. That is, theoretically, the current flowing through each part of the circuit device can be calculated by solving Maxwell's electromagnetic wave equation under predetermined boundary conditions. However, in general, Maxwell's equation is effective for simple boundary conditions, and not effective for complicated boundary conditions. Accordingly, a theoretical solution of the current has not been found in the case of complicated boundary conditions.
Accordingly, all solution methods for obtaining the current under complicated boundary conditions, which are utilized in the recent calculation apparatus for intensity of electromagnetic fields, employ an approximated solution method.
Three typical approximated solution methods are known, i.e., an approximated solution method using a very small loop antenna (below, a very small loop-antenna method), an approximated solution method using a distributed constant circuit (below, a distributed constant circuit method), and an approximated solution method using a moment (below, a moment method).
However, each of these three methods has advantages and disadvantages as explained below. The present invention takes advantage of the distributed constant circuit method and the moment method so that it is possible to realize high speed and high precision calculation of the intensity of the electromagnetic fields as explained in detail below.